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Q&A JOptionPane doesn't show; application combines Swing and console.

What is wrong in the following code: package oren; import java.util.Scanner; import javax.swing.JOptionPane; public class Main { public static void main(String[] args) { double x,y,z...

1 answer · posted 4mo ago by programAngel‭ · edited 4mo ago by FractionalRadix‭

Question java swing Eclipse

#6: Post edited by

FractionalRadix‭ · 2026-05-13T07:34:43Z (4 months ago)
Added OP's comment that there were no error messages. Changed title a little to make it clear that console input is involved (even if, in the end, that wasn't the problem). Added Eclipse tag because it turned out to be relevant (had no repro in IntelliJ).

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java swing + console . JOptionPane doesn't show

JOptionPane doesn't show; application combines Swing and console.

~~what is wrong in the following code:~~
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
~~For some reason the JOptionPane.showMessageDialog doesn't show.~~
~~I am using eclipse and java 21.~~

What is wrong in the following code:
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
For some reason the `JOptionPane.showMessageDialog` doesn't show.
However, there are no error messages.
I am using Eclipse and Java 21.

java swing

java swing Eclipse

#5: Post edited by

programAngel‭ · 2026-05-12T12:36:10Z (4 months ago)

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java swing + console wrong behaviour. what is the problem?

java swing + console . JOptionPane doesn't show

#4: Post edited by

programAngel‭ · 2026-05-12T12:33:07Z (4 months ago)

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what is wrong in the following code:
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
~~For some reason the JOptionPane.showMessageDialog never run.~~
I am using eclipse and java 21.

what is wrong in the following code:
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
For some reason the JOptionPane.showMessageDialog doesn't show.
I am using eclipse and java 21.

#3: Post edited by

programAngel‭ · 2026-05-09T15:01:15Z (4 months ago)

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what is wrong in the following code:
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
~~For some reason the JOptionPane.showMessageDialog never run.~~

what is wrong in the following code:
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
For some reason the JOptionPane.showMessageDialog never run.
I am using eclipse and java 21.

#2: Post edited by

samcarter‭ · 2026-05-09T15:00:05Z (4 months ago)
code markup

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java swing + console wrong behaviour. what is the problem?

what is wrong in the following code:
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
For some reason the JOptionPane.showMessageDialog never run.

what is wrong in the following code:
```
package oren;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
double x,y,z;
Scanner scanner = new Scanner(System.in);
System.out.println("what are the x and y side of the triangle");
x = scanner.nextDouble();
scanner.nextLine();
y = scanner.nextDouble();
scanner.nextLine();
scanner.close();
JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));
}
}
```
For some reason the JOptionPane.showMessageDialog never run.

#1: Initial revision by

programAngel‭ · 2026-05-09T14:34:12Z (4 months ago)

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java swing + console wrong behaviour. what is the problem?

what is wrong in the following code:

package oren;
import java.util.Scanner;

import javax.swing.JOptionPane;

public class Main {

	public static void main(String[] args) {
		double x,y,z;
		Scanner scanner = new Scanner(System.in);
		System.out.println("what are the x and y side of the triangle");
		x = scanner.nextDouble();
		scanner.nextLine();
		y = scanner.nextDouble();
		scanner.nextLine();
		scanner.close();
		JOptionPane.showMessageDialog(null, Math.sqrt(x*x + y*y));

		
	}

}

For some reason the JOptionPane.showMessageDialog never run.

java swing

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